In nuclear reactor plants ionic impurities are normally removed from the water in the primary circuit in the reactor by the use of ion exchange filters containing an organic ion exchange material. The water in the condensate cleaning circuit and in the discharge pipe is also normally subjected to purification in ion exchange filters of the same type. After being used for some time the ion exchange material becomes exhausted and must be taken care of and stored under safe conditions.
One known way of dealing with the ion exchange material, which is strongly hydrated, is to mix it with cement in storage containers, usually concrete moulds having a volume of a cubic meter, and to allow the cement to solidify. Another known way is to mix the ion exchange material, after drying, with bitumen and to store it in sheet-metal barrels. There are also different known ways of transferring or fixing the radioactive constituents into inorganic products, which are then finally stored.
The organic ion exchange material normally used consists of a mixture of grains bearing groups containing hydrogen ions (cationic grains) and grains bearing groups containing hydroxyl ions (anionic grains). After the material has been used, some of these groups still remain, namely those which have not been consumed during the use. This results in the grains of the two types in the material used being attracted to each other and being incapable of separation using reasonable efforts, if that should be desired.